Cestodes : Cestodes -Varun C N Slide 2: Diphyllobothrium latum (Fish tapeworm)
Longest tapeworm in humans
Has 3 parts- Scolex, neck and strobila
It bears 2 slit like grooves- “Bothria”
No rosetellum and hooklets 2 Varun C N- Cestodes Slide 3: Neck
Present below the scolex
Long in length compared to scolex
More than 3000 proglottids
Immature, mature and gravid proglottids
Hermaphroditic in nature
Eggs are discharged periodically
Single worm discharge as many as million eggs/ day 3 Varun C N- Cestodes Slide 4: Egg
Contains immature embryo
Not effective to humans
Thin eggs with operculum at one end and knob at other 4 Varun C N- Cestodes Slide 5: Definitive host- Humans
First Intermediate host- Small copepods
Second Intermediate host- Freshwater fishes
Infective form- Plerocercoid larva
Mode of infection- Ingestion of Fish containing larval forms 5 Varun C N- Cestodes Slide 6: Water Copepods Fish 6 Varun C N- Cestodes Slide 7: Clinical manifestations
Intestinal obstruction, diarrhea, and abdominal pain
Demonstration of eggs in fecal samples by
Concentrated by Formol-ether method 7 Varun C N- Cestodes Slide 8: Prophylaxis
Flash freezing of raw fish
Treat the carriers
Praziquantel or Niclosamide 8 Varun C N- Cestodes Slide 9: Taenia saginata
Taenia solium Other name
Taenia saginata- Beef tapeworm, unarmed tapeworm of man
Taenia solium- Pork tapeworm, armed tapeworm of man
Distribution- World wide 9 Varun C N- Cestodes Slide 10: 10 Varun C N- Cestodes Slide 11: 11 Varun C N- Cestodes Slide 12: T. saginata T. solium 12 Varun C N- Cestodes Slide 13: Figure A: Taenia saginata has 15 to 20 uterine branches in each segment (proglottid).Figure B: Taenia solium has 7 to 13 uterine branches 13 Varun C N- Cestodes Slide 14: Eggs:
Thick, striated shell.
Eggs of T.solium and T. saginata are indistinguishable and species identification should be made from proglottids or scoleces.
When excreted Embryonated. 6- hooked oncosphere present inside a thick shell. 14 Varun C N- Cestodes Slide 15: Life cycle 15 Varun C N- Cestodes Slide 16: 16 Varun C N- Cestodes Slide 17: 17 Varun C N- Cestodes Slide 18: Clinical symptoms
T saginata produces mild discomfort and abdominal pain
T solium larval forms develop in other parts of body and cause related symptoms.
The most dangerous is Neurocysticercosis
Other organ cysticercosis is also seen 18 Varun C N- Cestodes Slide 19: 19 Varun C N- Cestodes Slide 20: An extraordinary huge cysticercosis pseudo tumour 1.5kg was completely excised. Uledi SJ. A rare gigantic solitary cysticercosis pseudotumour of the neck. JSCR. 2010 9:5 20 Varun C N- Cestodes Slide 21: Lab diagnosis
Diagnosis of intestinal taeniasis can be made by recovery of the characteristic ova in the stool.
The diagnosis of cysticercosis depends upon serology
Calcified cysticerci are less often seen in the brain
Calcification in muscles usually appears three to five years after initial infection, and are most typically seen as spindle-shaped calcifications, most numerous in the thighs.
Occasionally, the diagnosis is made histologically on surgical specimens. 21 Varun C N- Cestodes Slide 22: Prophylaxis
All Meat consumed should be checked for cysticercosis
Proper sanitary disposal
Treat all infected people 22 Varun C N- Cestodes Slide 23: Hymenolepis nana (Dwarf tapeworm) H. nana is the most common cause of all cestode infections and is encountered worldwide 23 Varun C N- Cestodes Slide 24: Adult Worm
4 cup shaped suckers
Rosetellum armed with a single row of hooklets
Long and slender
About 200 proglottids
Genital pores are lateral 24 Varun C N- Cestodes Slide 25: Eggs:
On the inner of the two membranes surrounding are two poles, from which 4 to 8 polar filaments spread out between the two membranes.
The oncosphere, or larval stage, has six hooks. 25 Varun C N- Cestodes Slide 26: Life cycle
Infectious form: Mature Egg
Route of infection: Ingestion
Natural Host: Human
Reservoir Host; Rats
When eaten by a person or rodent, eggs hatch in the duodenum, releasing oncospheres, which penetrate the mucosa and come to lie in lymph channels of the villi.
Oncospheres develop into cysticercus larvae which have a neck behind a well formed scolex.
In five to six days cysticercoids emerge into the lumen of the small intestine, where they attach, mature, and produce eggs. 26 Varun C N- Cestodes Slide 27: 27 Varun C N- Cestodes Slide 28: Life cycle Direct Indirect 28 Varun C N- Cestodes Slide 29: Clinical symptoms
Infections due to H. nana may cause no symptoms even with heavy worm burdens.
Restlessness, irritability, anorexia, abdominal pain and diarrhea
Heavy worm burdens may be caused by auto-infection which can be a problem in the immunocompromised. Laboratory Diagnosis
Diagnosis is based on recovery and identification of the characteristic ova in a Formol-ether concentrate of feces.
Adult worms and proglottids are rarely seen in stool samples 29 Varun C N- Cestodes Slide 30: Don’t get Confused. This is not H nana. Its his brother- H diminuta No polar filaments 30 Varun C N- Cestodes Slide 31: Echinococcus granulosus 31 Varun C N- Cestodes Slide 32: Morphology
Pyriform in shape
4 suckers and a protrusible rosetellum
Double row of hooklets
Thick and short
3 segments- immature, mature and gravid 32 Varun C N- Cestodes Slide 33: Eggs:
Morphologically indistinguishable from Taenia species 33 Varun C N- Cestodes Slide 34: 34 Varun C N- Cestodes Slide 35: Life cycle:
Definitive hosts- Feline animals
Indefinitive hosts- Cattles
Accidental hosts- Man
Infective form- Mature Eggs
Mode of infection- Ingestion
Agent causing infection in humans- Larva 35 Varun C N- Cestodes Slide 36: 36 Varun C N- Cestodes Slide 37: Pericyst
Hydatid Fluid Fig: Structure of Hydatid Cyst 37 Varun C N- Cestodes Slide 38: Hydatid Fluid
Clear and pale yellow
Sp gravity of 1.005-1.010
pH is slight acidic (aprox 6.7)
Centrifuged deposits of hydatid fluid shows free solices, hooklets and detached brood capsules. It is called as hydatid sand. 38 Varun C N- Cestodes Slide 39: 39 Varun C N- Cestodes Slide 40: Laboratory diagnosis:
1. Casoni Test Man's arm showing positive skin test for hydatid disease 40 Varun C N- Cestodes Slide 41: 2. Serological diagnosis
3. Surgical removal of Hydatid cyst and examination
5. Radio diagnosis 41 Varun C N- Cestodes Slide 42: That’s all……….
The End 42 Varun C N- Cestodes